Place a rack in the center of the oven and preheat to 375 degrees. Coat a baking sheet with cooking spray then set aside.

Trim ends off zucchini then grate into a large mixing bowl using the largest holes of a cheese grater. Grate the onion into the same bowl. Toss the grated mixture with ½ tsp salt and set aside for about 10 minutes.

Transfer zucchini mixture to a strainer and press it firmly against the sides to extract as much liquid as possible to avoid soggy patties. You can also wrap the zucchini mixture up in a clean dishtowel and wring out the water.

Move the zucchini back to the mixing bowl. (You should only be left with about 2 cups of zucchini at this point.) Stir in all remaining ingredients until completely combined.

Scoop out batter in ¼-cup portions until all batter is used, drop onto prepared baking sheet and bake for 20 minutes. Turn the patties and bake for an additional 10–15 minutes until golden brown and crispy.

Remove from oven and sprinkle with additional salt (if necessary). Serve immediately so they stay nice and crispy!